Typical circuit traces made by PCB fabrication (printed circuit board) involve using complicated manufacturing process, such as processes of lithography and etching. Another typical circuitry manufacturing process involves using printed conductive inks. The drawbacks of using the printed conductive inks are that the material has high electrical resistance. It is still remaining a great challenge using the typical technologies to fabricate metal traces on a 3D object. Further, the typical mold interconnect device (MID) technology is too complicated and expensive to viably make 3D circuitry.